An exploration of the consequences of, and coping with loneliness in an ageing intellectual disability population

Background: Loneliness has been associated with increased hypervigilance and sad passivity. The physiological and psychological reactions of people with an intellectual disability to loneliness have never been investigated. Therefore, this research aims to explore the outcomes of loneliness for an ageing intellectual disability population. Methods: In Ireland, data from a nationally representative data set of people aged over 40 years with an intellectual disability (N=317) was applied to a social environment model that describes the effects of loneliness in five pre-disease pathways which are: health behaviours, exposure to stressful life events, coping, health and recuperation. The data was tested through chi-squared, ANCOVA and binary logistic regression. Results: Being lonely predicted raised systolic blood pressure (A.O.R=2.051, p=0.039), sleeping difficulties (AOR=2.526, p=0.002) and confiding in staff (AOR=0.464 p=0.008). Additionally, participants who did 10 to 20 minutes of exercise daily (moderate activity) had significantly higher loneliness scores than those who did not (F=4.171, p<0.05). Conclusions: The analysis supports the concept of hypervigilance in older people with an intellectual disability but finds that the health behaviours of the lonely do not differ from the not lonely. Future research needs to investigate the longitudinal relationships between loneliness and health


Introduction
Loneliness is the distressing feeling that accompanies discrepancies between one's desired and actual social relationships (Hawkley & Cacioppo, 2010). It is generally believed that the lonely tend not to seek help for their loneliness (Perlman & Peplau, 1998), withdrawing from others and using coping strategies that perpetuate their situation (Hawkley et al., 2008) such as self-blaming (Vanhalst et al., 2015) and lack of trust (Hensley et al., 2012).
Loneliness in older people has negative consequences for health and wellbeing, being associated with increased metabolic dysregulation (Shiovitz-Ezra & Parag, 2019) and increased systolic blood pressure (SBP) (Hawkley et al., 2010;Ong et al., 2012). Moreover, loneliness has been reported as altering a person's lifestyle and physiological reactions to stress (Hawkley & Cacioppo, 2007). In their social environment model of loneliness, Hawkley & Cacioppo (2007) argue that there are five pre-disease paths; health behaviours, exposure to stressful life events, coping style and support, physiology and recuperation, through which loneliness negatively influences a person's physiological resilience.
There is a growing body of evidence in older people to support each of the pre-disease pathways and their overall effect on physiological resilience. Hawkley & Cacioppo (2007) argue that unhealthy lifestyles contribute to poor health and early death in the first pathway health behaviours. Lonely people tend to be involved in more risky health behaviours (Shankar, 2017) and have been found to exercise less, smoke (Shankar et al., 2011), take in more fats and calories, and are more likely to have a higher body mass index (BMI) (Shiovitz-Ezra & Parag, 2019). It has been found that lonely people manage moods by eating, drinking and acting out sexually (Hawkley & Cacioppo, 2007), and they attend general practitioners surgeries and accident and emergency departments more frequently than those who are not lonely (Cleary, 2011). Contrary to this for people with an intellectual disability it has been reported that loneliness is not a predisposing variable for healthcare utilisation (McCallion et al., 2012).
In the second pathway, exposure to stressful life events, Hawkley & Cacioppo (2007) reported that the number of stressors experienced and the potency of those stressors are more prevalent in the lonely and diminish physiological resilience.
Lonely people report being exposed to an increased number of stressful life events and (Hawkley et al., 2008) some argue that it is the accumulation of negative life events that lead to loneliness in older people (Jylhä, 2004). However, the association between life events and loneliness is not consistently reported, and others have found no association (Zebhauser et al., 2015). The effect of each stressor is particular to an individual's circumstances. For instance, work stress has been reported to have more of an effect on unmarried people's loneliness (Hawkley et al., 2008). It is known that people with an intellectual disability experience more life events than found in the general population (Gilmore & Cuskelly, 2014), it is not known if these relates to loneliness.
In the third path, coping style, lonely people are less likely to cope by seeking a confidant for support (Victor et al., 2008) and are more likely to regularly attend church (Hawkley & Cacioppo, 2007). It is notable that people with an ID lack support from friends (The Money, 2012), spouses or life partners.
Consistent with the fourth pathway, the physiology of chronic stress in older people signal the vulnerability to disease. Chronic loneliness leads to activation of the autonomic nervous system, leading to heart rate and blood pressure increases (Hawkley et al., 2010). However, the effects of loneliness on cardiovascular health have recently been questioned, with one study claiming loneliness does not affect SBP (Das, 2019). However, Das (2019) has been criticised for not considering the role of medications beyond baseline (Hawkley & Schumm, 2019). Other researchers have reported that lonely people record a different cardiovascular response than non-lonely people in specific conditions (Brown et al., 2019). There is no evidence about physiological responses to loneliness in people with an ID.
Finally, recuperation counteracts the forces that drain physiological reserves. Lonely people have less effective sleep (Coyle & Dugan, 2012), their sleep is more fragmented (Kurina et al., 2011) or altered (Leigh-Hunt et al., 2017, they take more time to go to sleep and have more night-time disturbances than non-lonely people (Cacioppo et al., 2000). Sleep difficulties and loneliness in people with an intellectual disability have both been found to be predictive of mental health difficulties (Bond et al., 2020) but no research has as yet studied the relationship between sleep and loneliness in this group.
Perlman & Peplau (1998) claimed people had four mechanisms for coping with loneliness; sad passivity, active solitude, spending money and social contact. The evidence available tends to support the concept of sad passivity being the most common coping mechanism. People with an ID tend to be atypical of the general population in their health behaviours. It has already been reported that loneliness is not a predictor of healthcare utilisation in this population (McCallion et al., 2012). In general, people with an ID have healthier diets, smoke less, and drink less alcohol than the general population, but they complete very little vigorous physical exercise, and 66% are classified as overweight or obese (McCarron et al., 2014). Consideration of loneliness in people with ID must consider these different patterns of coping.

This research
While there is a developed body of evidence that supports the effects of loneliness on physiological resilience in the ageing population, the cumulative findings do not come from a single data set, and there is very little evidence to suggest the findings apply to people with an intellectual disability. This research uses the five pathway social-environmental model to investigate the consequences of loneliness in terms of physical and psychological reactions and coping mechanisms. How the health-effects are experienced can be influenced by other variables such as gender (Ward et al., 2021) and functional limitations (Wormald et al., 2019) which will therefore be covariates in this study. Using one source, the Intellectual Disability Supplement to The Irish Longitudinal Study of Ageing (IDS-TILDA) dataset seeks to answer the questions: how do older people with an ID physically react to loneliness?; and do lonely people with an ID demonstrate the use of specific coping mechanisms?

Ethical considerations
Ethical approval was granted from the Faculty of Health Sciences research ethics committee in Trinity College Dublin and all services providers involved in the study.

Study design.
The IDS-TILDA is a public patient involvement study that was codesigned with people with an intellectual disability and collects data from people aged over 40 years who are registered on the National Intellectual Disability Database (NIDD) about the ageing process. Data collection commenced in 2010. To date, three waves have been completed. The study encapsulated wide-ranging data including sociodemographic characteristics, social connectedness, physical and behavioural health, mental health, health care utilisation, employment and education, personal choices. The NIDD released 1800 personal identification numbers of potential participants, and the regional, national disability coordinator mailed invitation packs to each person. Participants were sent a consent pack, and where able, they self consented. Where people could not self consent, family/guardians consented on their behalf. Interviews are conducted directly with the participant, supported by a proxy or have the interview completed fully by a proxy. The proxy had to have known the participant for at least six months. Data was collected using a pre-interview questionnaire (PIQ), a face-to-face interview and a health fair. The PIQ was posted to the participants a week in advance of their face-to-face interview facilitating the participant to collect the required information and gain support for completion if required. The face-to-face interview utilised computer-assisted interviewing on encrypted laptops. The health fair was conducted separately from the main study and involved a researcher assessing eight health measures such as bone density, systolic blood pressure and weight.
This study is a cross-sectional analysis of wave 2 data. Wave 2 data was selected as it was the first wave to include the full 3-item i.e., a complete loneliness scale and use here prepares for future longitudinal comparisons to be addressed in future articles. In this study, we use the variables in the five pathway social-environmental model as dependent variables and test using the loneliness and social connectedness scale and co-variates as independent variables to understand the role of loneliness in each of these variables.

Participants
Participants for the IDS-TILDA study had to be registered on the National Intellectual Disability Database and aged over 40 years at wave one in 2010. Wave 2 data collection was conducted in 2013 interviews in this study can be either by the participant alone or the participant may have a proxy supporting them. In this analysis, participants must have self-reported their answers to the loneliness questions and must have supplied their systolic blood pressure reading. Most other measures were usually self-reported.

Measures
Loneliness and social connectedness scale. The loneliness and social connectedness scale consisted of four items: The Three-Item Loneliness Scale (Hughes et al., 2004) and a self-labelling loneliness item. To aid in comprehension and to simplify the response options, the questions were divided into two parts. The first part had a lead-in of "Do you ever feel….." with a yes/no response. Only if participants responded yes to the first part did they receive the second part of the question asked, "how often do you feel….." with a three-point response set (rarely/sometimes/always). For each of the four items responses were coded 1 for responding no to the first question or for rarely/never to the second question, 2 for sometimes and 3 for almost always. Where a single item score was missing, data was imputed on a person-mean basis. A total of 35 people (11.0%) were missing a single item. The most commonly missed item was, "Do you ever feel isolated?" The scale demonstrated satisfactory internal consistency (Chronbach's alpha = .715) scores ranged from 4 to 12, and the mean score was 5.30 (SD = 1.58), a score of four meaning no feelings of loneliness and a score of 12 meant the person was lonely always across all four items. For analysis in cross tabulations and the binary logistic regression the loneliness variable was dichotomised following the methodology of Pikhartova et al. (2016). Participants scoring in the bottom three quartiles scoring between 4 and 6 were categorised as not lonely (n=246), which equated to 77.6% of participants. Lonely participants were the top quartile who scored greater than six on the scale (n=71, 22.4%).
Health variables. All health variables were taken from the second wave of data collection and were selected to approximate those described by Hawkley & Cacioppo (2007) in their social environment model (n=317 unless otherwise stated).

Path 1 -Health behaviours
Path 1 included four binary-coded variables, Vigorous Activity, Moderate Activity, Mild Activity and Smoking. Participant responses were coded one for yes and zero for no. A measure of Body Mass Index (BMI) (n=248, 78.2%) was created for each participant using either height and weight or ulna measurement (Elia, 2003). Participants with a BMI of 30 or higher were classified as obese coded one. All others were coded zero. Self-reported diet (n=312, 98.45) was binary coded between excellent and very good, and good, fair or poor.
Path 2 -Exposure to stressful events The life events scale used was an adapted version of the Hermans & Evenhuis (2012) life events scale for older people with intellectual disabilities. The scale here used 19 of the 28 items. Participants were asked if they had experienced any items on the list of life events in the previous 12 months. Participants who indicated the presence of a life event were then asked how stressful they found that life event. Stress was scored on a three-point scale; one, a lot, two, a little and three, none. In total, 311 (98.1%) participants responded to the scale. The numbers of Life events experienced over the previous 12 months were counted, and participants were classified as either high on the number of life events experienced or normal. Stresses were separated into three categories; Social Stress, Relationship Stress and Service Stress.

Path 3 -Coping
The coping mechanisms tested were being a Church Attender and confiding in different groups, family, friend, staff and other; responses were binary coded.

Path 4 -Health
Systolic Blood Pressure (SBP) (n=224, 70.6%) was measured using an Omron 10 device with the results binary coded into two categories; those with a score over 120mmHg were coded as high SBP, and those scoring below 120mmHg were classified as normal blood pressure.

Path 5 -Recuperation
There were four sleep variables Trouble Falling Asleep (n=310, 97.8%), Interrupted Sleep (n=312, 98.4%), Waking Too Early (n=308, 97.1%) and Daytime Sleeping (n=310, 97.8%). Variables were dichotomised based on percentile. An overall sleep scale score was created by summing the scores of the four sleep items. Scores were binary coded between having difficulty sleeping and no difficulty sleeping.

Co-variates.
Functional limitations are measure using an 11 item self-reported scale aimed at measuring a participant's physical abilities. The scale was developed for use in the Health and Retirement Study (Wallace et al., 2004) and included questions such as "Please indicate the level of difficulty if any, you have with walking 100 yards" and "Please indicate the level of difficulty, if any, you have with bathing or showering." Participants were asked whether they had a problem doing each activity. Responses were scored one for no difficulty, two for some difficulty, three for a lot of difficulty, four for can't do it at all.

Analysis
All statistical analysis was undertaken using SPSS v23.0.
Analysis followed the three-step approach undertaken by Lauder et al. (2006). Step 1, cross-tabulations were constructed. Each path variable was cross-tabulated, first with the loneliness scale variable and then the consistent loneliness variable. This produced proportions of the lonely that were relative to each variable. The data in the tables were tested for independence using chi-square.
Step 2, separate analyses of covariance (ANCOVA) were conducted. The ANCOVAs included the loneliness scale score as the dependent variable and a path variable as the independent variable. Functional limitations and gender were co-variates.
Step 3, binary logistic regression, was used to investigate loneliness's role as a predictor variable of each path variable. Functional limitations and gender were listed as co-variates. The Naglekerke R² statistic was calculated, excluding co-variates, for each path variable, where either the loneliness scale score or consistent loneliness was a significant predictor of a path variable. Calculating the Naglekerke R², in this manner, allows the fit of the loneliness variable to each health variable to be understood. Nagelkerke R² is one of the two pseudo-R² measures available in SPSS v 23.0 and offers the benefit over the Cox-Snell method of being scaled 0-1.
For all analysis, 95% bootstrap bias-corrected and accelerated confidence intervals were produced with 5,000 cases.

Results
Participants for this study had to self-report their loneliness on the loneliness scale in wave two of data collection ( Figure 1). Table 1 represents the demographic breakdown of participants. Comparing those who completed the scale to those who did not complete the scale the average age of 56.16 (SD=8.578) was not significantly different for those who did not complete the scale (mean=56.95, SD=9.875). This subpopulation had a higher percentage of females (59.3%) than those that did not answer (46.3%), but there was no significant difference in the gender balance (χ²=2.691, p=0.101). There was an overrepresentation of those with mild and moderate disability in those who completed the loneliness scale compared to those who did not respond to the loneliness scale (χ²=179.190 p<0.001).
Cross-tabulations were calculated for each health variable against the dichotomised loneliness scale variable (Table 2). All cells had an expected value of more than five participants, allowing chi-squared analysis to be conducted. Analysis of the loneliness scale score found in path 3, the not lonely on the loneliness scale were more likely to confide in staff (χ²=6.625 p<0.05). In path 4, those who were lonely were more likely to have raised SBP (χ²=4.424, p<0.05). Analysis of path 5 revealed that those who were lonely were proportionally more likely to have difficulties  The mean loneliness scores were subject to ANCOVA, with gender and functional limitations being held constant (Table 3). Those who had difficulty falling asleep tended to be lonelier (mean = 6.000) than those who did not have difficulty falling asleep (mean = 5.150). In path 1, participants who did moderate activity had significantly higher loneliness scores (mean = 5.524) than those who did not (mean = 5.221, F=4.171, p<0.05). There were no significant results in Path 2.
In path 3, coping, those who confided in staff (mean = 5.152)

Discussion
This research offers the first evidence of how older people with an ID react to and cope with loneliness. The results indicate that older people with an ID reacted to loneliness with sleeping difficulties, raised systolic blood pressure, and were less likely to confide in staff/caregivers. The results also found that the lonely are more likely to take part in moderate physical activity.
This study supports previous research in the general population that indicated associations between loneliness and sleeping difficulties (Kurina et al., 2011) and loneliness and systolic blood pressure (Hawkley & Cacioppo, 2007). These findings also extend previous knowledge (Victor et al., 2008), indicating the importance of whom people confide in over merely confiding as an act. Finally, for people ageing with an ID, the results disagree with the general ageing population's findings that lonely people are more likely to have worse health behaviours than non-lonely (Hawkley & Cacioppo, 2007;Lauder et al., 2006). There was no association found between health behaviours and loneliness, and only those who did moderate activity were found more likely to score higher on the loneliness scale. Among people ageing with an ID, the lonely were twice as likely to have raised SBP. This evidence supports research from the wider population where it has been found that for every standard deviation rise in loneliness, SBP increased significantly (Ong et al., 2012). Although establishing a causal relationship remains for future research, a need is confirmed for attention to highlight blood pressure concerns among people with ID who report feelings of loneliness.
Hypervigilance has also been reported to cause people to be wary of others (Cacioppo & Cacioppo, 2014). Here, whom a person confided in influenced their chances of becoming lonely and additionally, being lonely influenced whom people confided in, creating a cycle of protection or harm. More specifically, those who confided in staff were less likely to be lonely, and those who were lonely were more than one and a half times more likely to confide in others. It is possible that people who confided in staff were confiding in someone who could make a difference to underlying issues, whereas others may not affect a person's circumstances directly.
In this study we found that those who took part in moderate activity scored significantly higher on the loneliness scale. Emotional and instrumental support has been found to enable engagement in physical exercise (Rackow et al., 2015). Considering this general population finding, one possible explanation for the moderate activity finding here is that compared to the wider population many of the people with intellectual disabilities in our study receive support from care workers (McCausland et al., 2018). Staff may have encouraged those they suspected of being lonely to engage in more exercise. The role of staff and other caregivers and linkage between increased physical activity and loneliness needs further investigation.

Implications
The findings here present a complex interaction between health issues and loneliness. Too often the presence of health symptoms results in assessment of health issues alone when assessment that includes loneliness and other psychosocial concerns may offer a better perspective on what needs to be addressed. Rather than professionals seen occasionally and focused on health concerns, it is care staff who are more likely to pick up concerns sleeping difficulties that may more likely be related to isolation and loneliness. Consistency by providers in assigning care staff will increase the likelihood of observing and reporting concerns and person centered planning to improve the quality of life and may be the most helpful approaches.

Limitations
In analysing the data as reactions to and coping with loneliness, this research may imply causality. To show causality, three criteria need to be met; covariation, temporal ordering and elimination of competing theories (Hayes, 2013). This analysis cannot prove causality since it is not an experiment controlling the above conditions; however, steps have been taken in the analysis to approximate the three criteria. Covariation was dealt with through the type of analysis conducted that showed the variables did have covariation. Two competing theories were accounted for through the utilisation of the co-variates gender and functional limitations. There are more than two possibilities for competing causes of the variables health paths, and these need to be considered with further investigation of the data. This analysis is the first work to look at how older people with an intellectual disability react to and cope with loneliness, and some results confirmed findings from the general population, further suggesting validity. Additional investigation assuming findings hold will add to the validity of the findings.
Likert type scales have been reported as problematic for people with an intellectual disability (Gilmore & Cuskelly, 2014).
However, others have found that people with an ID are capable of reliably answering three-point scales (Stancliffe et al., 2014), and the UCLA loneliness scale (Russell, 1996) has been found to adequately represent loneliness in those with cerebral palsy (Balandin et al., 2006).
The data used here were taken at a single time point and, therefore, do not have the support of longitudinal analysis. Unfortunately, the full loneliness scale was only available from wave two of data in the IDS-TILDA study. Further analysis will offer a more detailed insight as further waves of data also incorporating the scale become available.
The data collection techniques employed in this study meant that only people who could self-report their feelings are represented. This limitation excludes any understanding of loneliness in those who have difficulty communicating. In future research, alternative research methodologies must be employed to help those with communication difficulties express their feelings of loneliness.

Conclusion
This study was the first to explore reactions to and coping with loneliness in an ageing population of people with an ID. This study used a social environment model of loneliness described by Hawkley & Cacioppo (2007) that analysed the effects of loneliness on physiological resilience through five pre-disease paths. The results add support to path 4 (health effects) and path 5 (recuperation). They extend parts of path 3 (coping) but find little supporting evidence for paths 1 (health behaviours) and path 2 (exposure to stress). The analysis undertaken supports the concept of hypervigilance and suggests that it is experienced in this population, leading to sleep disruption, raised SBP and wariness of other people. The analysis does not support any hypothesised coping mechanisms (Perlman & Peplau, 1998), finding no differences in the health behaviours between the lonely and the non-lonely. Future research needs to investigate the longitudinal relationships of loneliness and health in this ageing ID population.

Underlying data
The data controller for this project is Trinity College Dublin Approval for data sharing was not sought at ethics approval stage nor was it included in the study information and consent forms provided to participants. The anonymised underlying data for this paper is available in a restricted format. Access to data which could potentially pose a risk to the confidentiality of IDS-TILDA participants has been withheld following assessment of sample size, cell counts and the data context. In the last sentence of the results, can you clarify who was the comparison group? The phrase 'moderate activity' already suggests a relatively high level of activity, but maybe this is just my impression of the wording.
engage in more exercise/activity where the person with ID is perceived to be isolated from peers. Isolated people in the general population often won't have that kind of support/external motivation to exercise.

Limitations:
You mention that participants must have self-reported their answers to the loneliness questions to be included in the study. Was any other information proxy-reported for the included cases? 1.

If applicable, is the statistical analysis and its interpretation appropriate? Yes
Are all the source data underlying the results available to ensure full reproducibility? Yes

Are the conclusions drawn adequately supported by the results? Partly
Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Public health, health of people with ID I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.

Author Response 29 Jun 2022
Andrew Wormald, Trinity College Dublin, Dublin, Ireland

Dear Reviewer
Thank you for taking the time to review this article. We have taken note of your constructive and helpful comments and we have acted upon each of them. You will find below a list of the amendments that have been included in the article based on your comments. Where we mention page numbers in our comments we are referring to the page number that can be found at the bottom of the page e.g. page 1 as they appear in the current document.
We hope you find these changes now bring the paper up to the required standard.

Many Thanks
The Authors
Thankyou, we have modified the sentence to read (page 2), "in five pre-disease pathways which are:" In the last sentence of the results, can you clarify who was the comparison group? The phrase 'moderate activity' already suggests a relatively high level of activity, but maybe this is just my impression of the wording.

○
To clarify this sentence, we have amended the wording around moderate exercise to read (Page 2): Additionally, participants who did 10 to 20 minutes of exercise daily (moderate activity) had significantly higher loneliness scores than those who did not (F=4.171, p<0.05).
In the first sentence of the conclusions, do you mean that there aren't enough IDspecific support initiatives? Please, clarify your point if possible.

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We have modified the first sentence of the conclusion on page 2 to read: The analysis supports there is a need for loneliness-focused hypervigilance among older people with an intellectual disability but supports that the health behaviours of the lonely do not differ from the not lonely. Introduction: The first paragraph is not really needed, as you make the same points in the next few paragraphs.

We have deleted the first paragraph as per your recommendation
You seem to refer to ID-specific studies availability or lack thereof only when discussing the third and fourth pathway. Can you please comment on other pathways too?

Path 1 added (page 3): Contrary to this for people with an intellectual disability it has been reported that loneliness is not a predisposing variable for healthcare utilisation
Path 2 (Page 3): It is known that people with an intellectual disability experience more life events than found in the general population (Gilmore & Cuskelly, 2014), it is not known if these relates to loneliness.

Path 5 (page 3): Sleep difficulties and loneliness in people with an intellectual disability have both been found to be predictive of mental health difficulties (Bond et al., 2020) but no research has as yet studied the relationship between sleep and loneliness in this group.
'The evidence available tends to support the concept of sad passivity being the most common coping mechanism.' -Can you please explain further how you reached this conclusion? ○ Thank you for pointing out your understanding of this statement. In the general population loneliness has been found to influence health behaviours in a way that fits the description of sad passivity. However, in this study there is no evidence to support the claim that loneliness has any influence on health behaviours of people with an intellectual disability. We have modified the paragraph on page 16 to read: The findings here present a complex interaction between health issues and loneliness. Too often the presence of health symptoms results in assessment of health issues alone when assessment that includes loneliness and other psychosocial concerns may offer a better perspective on what needs to be addressed. Rather than professionals seen occasionally and focused on health concerns, it is care staff who are more likely to pick up concerns sleeping difficulties that may more likely be related to isolation and loneliness. Consistency by providers in assigning care staff will increase the likelihood of observing and reporting concerns and person centred planning to improve the quality of life and may be the most helpful approaches.

Methods
Give justification for using wave 2 data which was 2013 and SPSS 23 which was 2015, why are we analyzing data from 2013 which is 9 years old especially when there is a wave 3, and if using SPSS 23 was the analysis done a number of years ago? ○ Measures -give 'n =' and '%' but not for all, please give both.

Findings
Participants who did moderate activity had significantly higher loneliness scores (higher than all other groups of activity levels -is it saying those who did moderate activity more likely to be lonely over those who do not or, low activity? And if so, bring out in discussion).

Discussion
Bring out implications is little research done based on your results what needs to happen e.g. if blood pressure or sleep issues present should a loneliness assessment be conducted or what strategies should be looked at to support people with ID and bring this out for the all the results you discuss i.e. implications.

If applicable, is the statistical analysis and its interpretation appropriate? Yes
Are all the source data underlying the results available to ensure full reproducibility?

Are the conclusions drawn adequately supported by the results? Yes
Competing Interests: No competing interests were disclosed.

Reviewer Expertise:
Intellectual disability, community support, nursing care.
I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.

Author Response 29 Jun 2022
Andrew Wormald, Trinity College Dublin, Dublin, Ireland

Dear Reviewer
Thank you for taking the time to review this article. We have taken note of your constructive and helpful comments and we have acted upon each of them. You will find below a list of the amendments that have been included in the article based on your comments. Where we mention page numbers in our comments we are referring to the page number that can be found at the bottom of the page e.g. page 1 as they appear in the current document.
We hope you find these changes now bring the paper up to the required standard.

Many Thanks
The Authors

Reviewer 1
Abstract. Minor flow/readability aspects to be addressed.

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Thank you, we have amended the abstract to improve readability. Introduction. Repeating needs to be omitted e.g. increased systolic blood pressure paragraphs 1 and 3.

○
We removed paragraph 1 from the introduction (page 2) which has removed the repeating of items in the literature. While accepting little research pertaining to intellectual disability (ID) and loneliness it would be good to get a handle as to what population you have to draw your information from is it older persons, mental health, etc.

○
The information in the literature review is generally drawn from the wider ageing population We have ensured that throughout the literature review we have specified the characteristics of the populations reported upon (pages 2 to 4). For example, on page 3 we say "There is a growing body of evidence in older people to support each of the predisease pathways and their overall effect on physiological resilience. Hawkley & Cacioppo (2007)". Methods. Give justification for using wave 2 data which was 2013 and SPSS 23 which ○ was 2015, why are we analyzing data from 2013 which is 9 years old especially when there is a wave 3, and if using SPSS 23 was the analysis done a number of years ago? Wave 2 data was used so that a baseline for future longitudinal analysis could be established. Wave 2 was the first wave to include the complete loneliness scale. Analysis of this data began with SPSS 23 to meet grant reporting and thesis requirements but was not prepared for an article until more recently.
We have added the following text to the Study Design section on page 5: Wave 2 data was selected as it was the first wave to include the full 3-item i.e., a complete loneliness scale and use here prepares for future longitudinal comparisons to be addressed in future articles.
Measures -give 'n =' and '%' but not for all, please give both.

○
Within the Measures section we have ensured that each variable has the n and the % for example we have modified the information on Body mass index on page 6 to read: A measure of Body Mass Index (BMI) (n=248, 78.2%) was created for each participant using either height and weight or ulna measurement (Elia, 2003).
Findings. Participants who did moderate activity had significantly higher loneliness scores (higher than all other groups of activity levels -is it saying those who did moderate activity more likely to be lonely over those who do not or, low activity? And if so, bring out in discussion).

○
Thank you for highlighting this issue -we have now included the following in the discussion (page 16) about physical activity. In this study we found that those who took part in moderate activity scored significantly higher on the loneliness scale. Emotional and instrumental support has been found to enable engagement in physical exercise (Rackow et al., 2015). Considering this general population finding, one possible explanation for the moderate activity finding here is that compared to the wider population many of the people with intellectual disabilities in our study receive support from care workers (McCausland et al., 2018). Staff may have encouraged those they suspected of being lonely to engage in more exercise. The role of staff and other caregivers and linkage between increased physical activity and loneliness needs further investigation Discussion. Bring out implications is little research done based on your results what needs to happen e.g. if blood pressure or sleep issues present should a loneliness assessment be conducted or what strategies should be looked at to support people with ID and bring this out for the all the results you discuss i.e. implications.

○
On page 17 we have added the following implications to the discussion: The findings here present a complex interaction between health issues and loneliness. Too often the presence of health symptoms results in assessment of health issues alone when assessment that includes loneliness and other psychosocial concerns may offer a better perspective on what needs to be addressed. Rather than professionals seen occasionally and focused on health concerns, it is care staff who are more likely to pick up concerns about sleeping difficulties that may more likely be related to isolation and loneliness. Consistency by providers in assigning care staff will increase the likelihood of observing and reporting concerns and person centred planning to improve the quality of life and may be the most helpful approaches.